This invention relates to a machine for polishing wheel rims and the like, which permits the wheel rims to be polished without requiring subsequent manual polishing of the zones of most difficult access.
There currently exist rotary polishing machines which carry out polishing of a piece as that piece passes through a number of polishing units. In all these machines each carrying unit is driven by means of a positioning motor, which places the piece to be polished in a suitable position for carrying out the polishing operation to be carried out on each polishing unit.
Such motors are usually mounted on the table, that is, beside the carrying unit, and they rotate at the same time as the latter. The main disadvantage of the known machines is the power supply of the motor, due to the fact that the motor rotates with the table. This disadvantage is currently resolved by providing power to the machines by means of brushes. However, owing to the fact that each polishing unit carries out different operations depending on the polishing unit with which it works, it is costly and complex to achieve positioning of the piece using a conventional motor. This disadvantage means that motors of another type, usually known as Brushless motors, have to be fitted. Said motors permit precise positioning of the piece in each polishing unit, but they have the disadvantage that the electricity supply has to be very precise, which cannot be achieved using brushes.
The polishing machine described in Spanish utility model U9602541, from the holder of this application, was designed in order to resolve these disadvantages, for on it each polishing unit has associated a positioning motor for the carrying unit which is situated facing the polishing unit. Moreover, the carrying unit which is situated facing a polishing unit is coupled to the corresponding positioning motor by means of a shaft that moves vertically by kinetic force attached to the carrying unit, whose lower end is coupled to a base piece attached in rotation to the motor when, upon rotation of the table, the carrying unit is situated facing the polishing unit.
At present, the polishing of wheel rims is carried out entirely manually or by adapting the currently known polishing machines for the polishing of wheel rims, such as that described in Spanish utility model U9602541.
However, this machine which resolved the drawbacks outlined above has been shown to be not very suitable for polishing very complex pieces, such as wheel rims, which can have designs that differ markedly from one another. It has been found in practice that the wheel rim zones of most difficult access are not left suitably polished, and have to be polished manually.
The polishing machine of the invention manages to resolve the aforesaid drawbacks, while presenting other advantages which are described below.
The polishing machine of the invention for wheel rims and the like comprises a plurality of carrying units mounted on a turntable, with each of the carrying units securing a wheel rim or the like to be polished, and a plurality of polishing units, each one of which includes a polishing element that carries out a polishing operation on the wheel rim, in such a way that for each position of the turntable each one of the carrying units is situated facing a polishing unit, and is characterized in that the central shaft of each carrying unit is inclined with respect to the horizontal by a predetermined angle.
Thanks to this feature, it is possible to polish a wheel rim or the like completely, since access to the internal surface thereof is much easier than on the currently known polishing machines. With the polishing machine of this invention it is not necessary to polish manually the parts of the wheel rim which it is more difficult to reach.
Preferably, said predetermined angle is between 35xc2x0 and 55xc2x0.
Advantageously, the central shaft of each of the aforesaid polishing elements is perpendicular to the tangent of the turntable.
In order to achieve correct polishing of the entire surface of the wheel rim, the polishing unit rotates around a horizontal shaft parallel to the tangent of the turntable.
Preferably, each carrying unit includes means for securing the wheel rim or the like, which means are driven fluid dynamically.
Also preferably, said carrying units rotate around their inclined central shaft.
In order to drive their rotation, each carrying unit has an associated fixed motor situated on the turntable, the rotation shaft of the motor being coupled to means of transmitting the rotation to the carrying unit.
Advantageously, the polishing units can move towards and away from the turntable and can also move vertically. Moreover, the polishing units can also move laterally parallel to the tangent of the table.
So that the movements of the machine as a whole are suited to the design of the wheel rim or the like to be polished, the machine includes control means that synchronize the movements of the carrying units and the polishing units.